Digital camera modules have been developed as components for use in electronic apparatus such as personal digital assistants (PDAs) and mobile telephones.
FIGS. 1 to 4 illustrate such a digital camera module 100. FIG. 1 is a perspective top view of the module, FIG. 2 is a front side view of the module, FIG. 3 is a top plan view of the module, and FIG. 4 is a bottom plan view of the module. The module 100 comprises a substrate 110 and a lens structure 130.
The substrate 110 may be a rectangular-shaped ceramic substrate comprising electronic circuitry including an image sensor 116 on a top surface, and metallic terminals 114 on a bottom surface 112 for electrically coupling the module 100 to external circuitry.
The lens structure 130 comprises a rectangular-shaped base portion 135, and a turret portion 150 extending from the base portion 135. The base portion 135 and the turret portion 150 may both be formed of a plastics material. The turret portion 150 defines an aperture 160 through which light is received into the camera module for detection by the image sensor 116. A lens 170 is positioned within the aperture 160 for focusing received light onto the image sensor 116.
A drawback with known digital camera modules is that they are difficult to connect to printed wiring boards (PWBs). Reflow soldering of the ceramic substrate terminals 114 to a PWB is problematic as the plastics used in the lens 170 melt at temperatures less than the reflow temperatures. Reflow soldering may be possible if the lens is made from a glass material. However, glass lenses are expensive and are less suitable for mass production techniques.
One method for connecting a digital camera module to a PWB involves using a flexible intermediate substrate. The flexible substrate is glued at one end to the bottom surface 112 of the ceramic substrate 110 with locally-conductive adhesive such that the substrate terminals 114 electrically couple to electrical traces in the flexible substrate. The other end of the flexible substrate is then connected to the PWB via a FPC connector. This method is labor intensive and does not lend itself to automated assembly easily.